Dr. Andrew Nelson | Naval Air Warfare Center Weapons Division

WP-201507

Objective

This project will demonstrate the ability of the new Resonant Acoustic® Mixing (RAM) technology to produce energetic weapons systems components in a single processing step and quantify the reduction in processing waste generated as compared to legacy manufacturing techniques.

Technology Description

The current state of the art for producing cast cured, high energy, composite materials involves at least two key processing steps. In the first step, the composite material is mixed in a large bowl until all the formulation ingredients are incorporated into one homogenous material. Once the mixing is complete, the material is then cast in a second operation step into the desired end state (rocket motor case, warhead case, igniter stick, etc.) and cured at a prescribed temperature and time to form a solid composite suitable for weapons system integration.

The RAM technology is a new approach to processing in which low-frequency, high-intensity vibrations are used in place of impeller blades to generate the shear field necessary to process high solids loaded composite formulations. A key advantage of mixing without impeller blades is the ability to use the desired end item (rocket motor case, warhead case, igniter stick etc.) as the mixing container. This process of “in-situ mixing and casting” eliminates the need for a batch mixing bowl that must be cleaned up at the end of each production run. This advantage will reduce the amount of composite waste generated and cleaning solvents used during the production of weapons systems components. The lack of impeller blades will also reduce the contact between the mixing technicians and the energetic material by eliminating the need to scrape down and clean the mixer blades and bowl. The RAM-based process of mixing within the desired end item has not yet been demonstrated at the production scale for an energetic formulation.

In this project, hold down fixtures capable of securing multiple munition cases to the vibrating platforms of both the research scale LabRAM mixer and the industrial scale RAM5 mixer will be designed and fabricated. Next, the ability to mix and cast composite energetic materials to produce weapon system components in a single process will be demonstrated. The quantity of waste generated from the RAM mixes will be measured and compared to analogous production processes using similarly sized traditional mixers. The amount of waste generated per unit produced will be reported as the key environmental metric of the project.

Benefits

This new processing technology aims to reduce hazardous waste generated, increase personnel safety, and provide logistical and financial benefits. Eliminating the mixing bowl and blades will reduce the amount of waste composite that must be disposed of following each production mix. Eliminating the need to scrape the blades of the mixer during the production process will improve personnel safety by reducing the contact between the operation personnel and the hazardous material. Eliminating the batch mixing bowl will also reduce the amount of cleaning solvent used during restoration of the production facilities. This technology will result in lower supply costs and reduce the cost of disposal. The RAM technology may also reduce the logistical cost of weapons production by providing the ability to produce the components on demand. Because the RAM mixer does not use an integrated mixing bowl that must be cleared of one material before another can be prepared, a single RAM mixer can be used to produce any number of weapons system components and need not be dedicated to a single material or process. In this way the RAM technology is more agile in adapting to potential changes in production demand. (Anticipated Project Completion - 2018)